For type-II spin-singlet superconductors, the orbital and Pauli paramagnetic effects are two distinct ways for pair-breaking with increasing external magnetic field. Using \(2\Delta /k_BT_c\) =4.7\(\pm \) 0.3, the Pauli-limiting field \(H_P\) =45.4\(\pm \) 2.2 T is then determined accurately from \(H_P=\Delta /(\sqrt{2}\mu _B)\)  [1]} with \(\mu _B\)  being the Bohr magneton. The obtained orbital component of the upper critical field \(H_{c2}^{orb}\)  of 22 T is much smaller than \(H_P\) , yielding the Maki parameter [2]} \(\gamma =\sqrt{2}H_{c2}^{orb}/H_P\sim 0.7\) . Since \(\gamma \)  reflects the strength of the paramagnetic effect, this indicates that the orbital effect dominates the \(H_{c2}\)  behaviour for this superconductor.
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